A colored polymer particle constituting a toner for electrophotographic use and a colored polymer particle being applied to a carrier for immunologically diagnosing reagent are required to have a particle-size as small as possible. In the field of toners for electrophotographic use, for example, it is not only to expect to obtain a toner having a small particle-size and a narrow range of particle-size distribution, which has been hardly obtained in any conventional kneading/pulverizing process, in such a manner that colored polymer particles having a small particle-size are plurally associated and are then heatedly fused so that a toner particle may be synthesized, but also expected that a toner having a high pigment dispersibility and, accordingly, a high image transparency may be obtained, and that the toner configuration may further readily be controlled. However, it has not been able to realize the expectations in the conventional kneading/pulverizing process, as described above.
A carrier for immunologically diagnosing reagent use has been demanded to be a colored polymer particle having a small particle-size, from the viewpoints of the sharpness of a cohesion image and the speed of an immune cohesion reaction.
For realizing the demand, a polymer particle itself is required to have a satisfactory dispersion stability and to be stable in a step for compounding a pigment serving as a colorant. As for a toner for electrophotographic use, it is required to induce no unnecessary cohesion in a step for associating particles. As for a carrier for immunologically diagnosing reagent use, it is required to be stable when sensitizing an immunologically active species such as an antigen, an antibody and so forth and also to be so satisfactory in storage stability that the carrier dispersion state is invariable even when storing for a long time.
It is an object of the invention to securely provide a process in which the above-mentioned problems can be solved and a pigment-including polymer particle having a satisfactory dispersion stability can be prepared and, further, a toner for electrophotographic use having a particle-size and a particle-size distribution each controlled by making use of the pigment-composite polymer particle.
In other words and to be more concrete, it is an object of this invention is to provide a stable pigment-including polymer particle.
Another object of the invention is to provide a pigment-including polymer particle containing a finely particle-sized pigment excellent in spectral characteristics, light fastness and color fading resistance.
A further object of the invention is to provide a toner for electrophotographic use excellent in spectral characteristics, light fastness and color fading resistance, and improved in the dispersibility of a pigment.
Still further object of the invention is to provide a carrier for immunologically diagnosing reagent use ready for observing a coagulation image and excellent in stability.